In Tassie we have had a similar system for the last 10 years or so
http://www.transport.tas.gov.au/registration/conditional/special_interest In a nutshell it allows 52 days use per year
Reduced registration cost (under $200 / year for a 6 cylinder), however you must also own another full registered vehicle in your name.
Car must have a full vehicle inspection (roadworthy) prior to issuing SI (special interest rego plates)
SI rego not transferable so if vehicle sold it must be re-inspected.
Vehicle must be in good to excellent condition and you require a full engineers certificate for any modifications (except for minor stuff like slightly bigger wheels, minor carb changes etc).
It works out well and most people don't abuse the system and you don't see any rusty old bombs on SI rego.
I personally have a couple of vehicles on SI rego and you haven't gone anywhere near the maximum of 52 days usage per year. It also allows much cheaper insurance as insurance companies consider it very limited use and thus reduced fees.